Alginate constitutes 30%–60% of the polysaccharide content in brown seaweed and represents a promising renewable resource. However, its high molecular weight and complex block structure have limited industrial applications. The research team heterologously expressed alyB and alyD genes from the marine bacterium Vibrio algivorus in C. glutamicum, an industrial workhorse traditionally used for amino acid production.
Findings revealed that AlyB and AlyD possess distinct but complementary modes of action. AlyB exhibits endo-activity, cleaving alginate internally to produce oligomers, while AlyD acts exo-lytically on these products to release monosaccharides. Together, they achieve complete depolymerization. Notably, the researchers discovered that AlyB displays C-5 epimerization activity, which is the first report of such activity in the PL7 family of polysaccharide lyases.
To demonstrate practical application, the team used the enzyme-treated alginate to support growth of engineered E. coli producing riboflavin (vitamin B₂), achieving concentrations of 2.1 μg/mL. The research provides a foundation for developing integrated bioprocesses that couple alginate degradation with biosynthesis, potentially enabling sustainable production of food additives, biochemicals, and biofuels from seaweed resources.
The work entitled “Heterologous expression and functional characterization of two alginate lyases in Corynebacterium glutamicum” was published on Systems Microbiology and Biomanufacturing (published on January 07, 2026).
DOI: 10.1007/s43393-025-00432-6